The present invention relates generally to cabinets for a fan coil unit for use in heating and cooling, and, more particularly, to an improved polygon cabinet consisting of a number of identical side pieces with an interlocking mechanism, a bottom pan, and a top pan and a method of assembling the cabinet and fan coil unit.
A typical split air conditioning system, which might be a heat pump, includes an outdoor heat exchange unit having an outdoor heat exchanger, compressor, controls and a reversing valve, and an indoor unit. The indoor unit includes an indoor heat exchanger, supplemental heaters when using a heat pump, and a fan for circulating indoor air to be conditioned in heat exchange relation with the indoor heat exchanger. The indoor unit is connected by two refrigerant lines to the outdoor unit and is generally located within the space to be conditioned. Typically, in a cooling mode of operation, the liquid refrigerant is evaporated in the indoor heat exchanger absorbing its heat of vaporization from the air to be cooled, while in the heating mode of operation, the gaseous refrigerant is condensed to heat the indoor air by discharging its heat of condensation to the air being circulated in heat exchange relation with the heat exchanger. Accordingly, supplemental heaters, generally spaced between the coil and the cabinet, may be needed when using a heat pump.
The indoor heat exchanger is typically arranged to allow the fan to draw return air from the enclosure to be conditioned to the indoor unit and for the same fan to circulate air through the heat exchanger for conditioning the air and then back to the space to be conditioned. The indoor heat exchanger is typically operated under the control of the thermostat located in the space to be conditioned. The thermostat acts to control both the refrigeration circuit and the fan.
The present indoor unit cabinet is designed in a specific configuration to effectively utilize a cylindrical heat exchanger and to provide a compact unit having spaced peripheral duct openings about the circumference such that numerous ducts may be connected to the indoor unit for supplying conditioned air to the appropriate spaces within the enclosure. Additionally, a centrifugal fan is mounted on the cabinet and projects into the control space of the cylindrical heat exchanger. The fan is operated without utilizing a fan scroll such that return air is drawn inwardly into the fan along the central axis thereof and is discharged outwardly through the heat exchanger to the duct openings and then through the ducts. By utilizing a cylindrical heat exchanger and a polygon cabinet the air is evenly distributed through the entire heat exchanger and is thereafter evenly distributed to the individual ducts of each space to be conditioned.
The disclosed cabinet construction provides for a reduced physical volume (up to 50% less than conventional fan coil units), and provides variable supply air outlets for zoning purposes depending on the requirements. Additionally, by providing duct outlets spaced about the cabinet rather than a large single plenum discharge, low installation costs are promoted since each duct may be simply connected to a duct outlet.